| /** |
| * \file chachapoly.h |
| * |
| * \brief This file contains the AEAD-ChaCha20-Poly1305 definitions and |
| * functions. |
| * |
| * ChaCha20-Poly1305 is an algorithm for Authenticated Encryption |
| * with Associated Data (AEAD) that can be used to encrypt and |
| * authenticate data. It is based on ChaCha20 and Poly1305 by Daniel |
| * Bernstein and was standardized in RFC 7539. |
| * |
| * \author Daniel King <damaki.gh@gmail.com> |
| */ |
| |
| /* |
| * Copyright The Mbed TLS Contributors |
| * SPDX-License-Identifier: Apache-2.0 |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); you may |
| * not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT |
| * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| #ifndef MBEDTLS_CHACHAPOLY_H |
| #define MBEDTLS_CHACHAPOLY_H |
| #include "mbedtls/private_access.h" |
| |
| #include "mbedtls/build_info.h" |
| |
| /* for shared error codes */ |
| #include "mbedtls/poly1305.h" |
| |
| /** The requested operation is not permitted in the current state. */ |
| #define MBEDTLS_ERR_CHACHAPOLY_BAD_STATE -0x0054 |
| /** Authenticated decryption failed: data was not authentic. */ |
| #define MBEDTLS_ERR_CHACHAPOLY_AUTH_FAILED -0x0056 |
| |
| #ifdef __cplusplus |
| extern "C" { |
| #endif |
| |
| typedef enum |
| { |
| MBEDTLS_CHACHAPOLY_ENCRYPT, /**< The mode value for performing encryption. */ |
| MBEDTLS_CHACHAPOLY_DECRYPT /**< The mode value for performing decryption. */ |
| } |
| mbedtls_chachapoly_mode_t; |
| |
| #if !defined(MBEDTLS_CHACHAPOLY_ALT) |
| |
| #include "mbedtls/chacha20.h" |
| |
| typedef struct mbedtls_chachapoly_context |
| { |
| mbedtls_chacha20_context MBEDTLS_PRIVATE(chacha20_ctx); /**< The ChaCha20 context. */ |
| mbedtls_poly1305_context MBEDTLS_PRIVATE(poly1305_ctx); /**< The Poly1305 context. */ |
| uint64_t MBEDTLS_PRIVATE(aad_len); /**< The length (bytes) of the Additional Authenticated Data. */ |
| uint64_t MBEDTLS_PRIVATE(ciphertext_len); /**< The length (bytes) of the ciphertext. */ |
| int MBEDTLS_PRIVATE(state); /**< The current state of the context. */ |
| mbedtls_chachapoly_mode_t MBEDTLS_PRIVATE(mode); /**< Cipher mode (encrypt or decrypt). */ |
| } |
| mbedtls_chachapoly_context; |
| |
| #else /* !MBEDTLS_CHACHAPOLY_ALT */ |
| #include "chachapoly_alt.h" |
| #endif /* !MBEDTLS_CHACHAPOLY_ALT */ |
| |
| /** |
| * \brief This function initializes the specified ChaCha20-Poly1305 context. |
| * |
| * It must be the first API called before using |
| * the context. It must be followed by a call to |
| * \c mbedtls_chachapoly_setkey() before any operation can be |
| * done, and to \c mbedtls_chachapoly_free() once all |
| * operations with that context have been finished. |
| * |
| * In order to encrypt or decrypt full messages at once, for |
| * each message you should make a single call to |
| * \c mbedtls_chachapoly_crypt_and_tag() or |
| * \c mbedtls_chachapoly_auth_decrypt(). |
| * |
| * In order to encrypt messages piecewise, for each |
| * message you should make a call to |
| * \c mbedtls_chachapoly_starts(), then 0 or more calls to |
| * \c mbedtls_chachapoly_update_aad(), then 0 or more calls to |
| * \c mbedtls_chachapoly_update(), then one call to |
| * \c mbedtls_chachapoly_finish(). |
| * |
| * \warning Decryption with the piecewise API is discouraged! Always |
| * use \c mbedtls_chachapoly_auth_decrypt() when possible! |
| * |
| * If however this is not possible because the data is too |
| * large to fit in memory, you need to: |
| * |
| * - call \c mbedtls_chachapoly_starts() and (if needed) |
| * \c mbedtls_chachapoly_update_aad() as above, |
| * - call \c mbedtls_chachapoly_update() multiple times and |
| * ensure its output (the plaintext) is NOT used in any other |
| * way than placing it in temporary storage at this point, |
| * - call \c mbedtls_chachapoly_finish() to compute the |
| * authentication tag and compared it in constant time to the |
| * tag received with the ciphertext. |
| * |
| * If the tags are not equal, you must immediately discard |
| * all previous outputs of \c mbedtls_chachapoly_update(), |
| * otherwise you can now safely use the plaintext. |
| * |
| * \param ctx The ChachaPoly context to initialize. Must not be \c NULL. |
| */ |
| void mbedtls_chachapoly_init( mbedtls_chachapoly_context *ctx ); |
| |
| /** |
| * \brief This function releases and clears the specified |
| * ChaCha20-Poly1305 context. |
| * |
| * \param ctx The ChachaPoly context to clear. This may be \c NULL, in which |
| * case this function is a no-op. |
| */ |
| void mbedtls_chachapoly_free( mbedtls_chachapoly_context *ctx ); |
| |
| /** |
| * \brief This function sets the ChaCha20-Poly1305 |
| * symmetric encryption key. |
| * |
| * \param ctx The ChaCha20-Poly1305 context to which the key should be |
| * bound. This must be initialized. |
| * \param key The \c 256 Bit (\c 32 Bytes) key. |
| * |
| * \return \c 0 on success. |
| * \return A negative error code on failure. |
| */ |
| int mbedtls_chachapoly_setkey( mbedtls_chachapoly_context *ctx, |
| const unsigned char key[32] ); |
| |
| /** |
| * \brief This function starts a ChaCha20-Poly1305 encryption or |
| * decryption operation. |
| * |
| * \warning You must never use the same nonce twice with the same key. |
| * This would void any confidentiality and authenticity |
| * guarantees for the messages encrypted with the same nonce |
| * and key. |
| * |
| * \note If the context is being used for AAD only (no data to |
| * encrypt or decrypt) then \p mode can be set to any value. |
| * |
| * \warning Decryption with the piecewise API is discouraged, see the |
| * warning on \c mbedtls_chachapoly_init(). |
| * |
| * \param ctx The ChaCha20-Poly1305 context. This must be initialized |
| * and bound to a key. |
| * \param nonce The nonce/IV to use for the message. |
| * This must be a readable buffer of length \c 12 Bytes. |
| * \param mode The operation to perform: #MBEDTLS_CHACHAPOLY_ENCRYPT or |
| * #MBEDTLS_CHACHAPOLY_DECRYPT (discouraged, see warning). |
| * |
| * \return \c 0 on success. |
| * \return A negative error code on failure. |
| */ |
| int mbedtls_chachapoly_starts( mbedtls_chachapoly_context *ctx, |
| const unsigned char nonce[12], |
| mbedtls_chachapoly_mode_t mode ); |
| |
| /** |
| * \brief This function feeds additional data to be authenticated |
| * into an ongoing ChaCha20-Poly1305 operation. |
| * |
| * The Additional Authenticated Data (AAD), also called |
| * Associated Data (AD) is only authenticated but not |
| * encrypted nor included in the encrypted output. It is |
| * usually transmitted separately from the ciphertext or |
| * computed locally by each party. |
| * |
| * \note This function is called before data is encrypted/decrypted. |
| * I.e. call this function to process the AAD before calling |
| * \c mbedtls_chachapoly_update(). |
| * |
| * You may call this function multiple times to process |
| * an arbitrary amount of AAD. It is permitted to call |
| * this function 0 times, if no AAD is used. |
| * |
| * This function cannot be called any more if data has |
| * been processed by \c mbedtls_chachapoly_update(), |
| * or if the context has been finished. |
| * |
| * \warning Decryption with the piecewise API is discouraged, see the |
| * warning on \c mbedtls_chachapoly_init(). |
| * |
| * \param ctx The ChaCha20-Poly1305 context. This must be initialized |
| * and bound to a key. |
| * \param aad_len The length in Bytes of the AAD. The length has no |
| * restrictions. |
| * \param aad Buffer containing the AAD. |
| * This pointer can be \c NULL if `aad_len == 0`. |
| * |
| * \return \c 0 on success. |
| * \return #MBEDTLS_ERR_POLY1305_BAD_INPUT_DATA |
| * if \p ctx or \p aad are NULL. |
| * \return #MBEDTLS_ERR_CHACHAPOLY_BAD_STATE |
| * if the operations has not been started or has been |
| * finished, or if the AAD has been finished. |
| */ |
| int mbedtls_chachapoly_update_aad( mbedtls_chachapoly_context *ctx, |
| const unsigned char *aad, |
| size_t aad_len ); |
| |
| /** |
| * \brief Thus function feeds data to be encrypted or decrypted |
| * into an on-going ChaCha20-Poly1305 |
| * operation. |
| * |
| * The direction (encryption or decryption) depends on the |
| * mode that was given when calling |
| * \c mbedtls_chachapoly_starts(). |
| * |
| * You may call this function multiple times to process |
| * an arbitrary amount of data. It is permitted to call |
| * this function 0 times, if no data is to be encrypted |
| * or decrypted. |
| * |
| * \warning Decryption with the piecewise API is discouraged, see the |
| * warning on \c mbedtls_chachapoly_init(). |
| * |
| * \param ctx The ChaCha20-Poly1305 context to use. This must be initialized. |
| * \param len The length (in bytes) of the data to encrypt or decrypt. |
| * \param input The buffer containing the data to encrypt or decrypt. |
| * This pointer can be \c NULL if `len == 0`. |
| * \param output The buffer to where the encrypted or decrypted data is |
| * written. This must be able to hold \p len bytes. |
| * This pointer can be \c NULL if `len == 0`. |
| * |
| * \return \c 0 on success. |
| * \return #MBEDTLS_ERR_CHACHAPOLY_BAD_STATE |
| * if the operation has not been started or has been |
| * finished. |
| * \return Another negative error code on other kinds of failure. |
| */ |
| int mbedtls_chachapoly_update( mbedtls_chachapoly_context *ctx, |
| size_t len, |
| const unsigned char *input, |
| unsigned char *output ); |
| |
| /** |
| * \brief This function finished the ChaCha20-Poly1305 operation and |
| * generates the MAC (authentication tag). |
| * |
| * \param ctx The ChaCha20-Poly1305 context to use. This must be initialized. |
| * \param mac The buffer to where the 128-bit (16 bytes) MAC is written. |
| * |
| * \warning Decryption with the piecewise API is discouraged, see the |
| * warning on \c mbedtls_chachapoly_init(). |
| * |
| * \return \c 0 on success. |
| * \return #MBEDTLS_ERR_CHACHAPOLY_BAD_STATE |
| * if the operation has not been started or has been |
| * finished. |
| * \return Another negative error code on other kinds of failure. |
| */ |
| int mbedtls_chachapoly_finish( mbedtls_chachapoly_context *ctx, |
| unsigned char mac[16] ); |
| |
| /** |
| * \brief This function performs a complete ChaCha20-Poly1305 |
| * authenticated encryption with the previously-set key. |
| * |
| * \note Before using this function, you must set the key with |
| * \c mbedtls_chachapoly_setkey(). |
| * |
| * \warning You must never use the same nonce twice with the same key. |
| * This would void any confidentiality and authenticity |
| * guarantees for the messages encrypted with the same nonce |
| * and key. |
| * |
| * \param ctx The ChaCha20-Poly1305 context to use (holds the key). |
| * This must be initialized. |
| * \param length The length (in bytes) of the data to encrypt or decrypt. |
| * \param nonce The 96-bit (12 bytes) nonce/IV to use. |
| * \param aad The buffer containing the additional authenticated |
| * data (AAD). This pointer can be \c NULL if `aad_len == 0`. |
| * \param aad_len The length (in bytes) of the AAD data to process. |
| * \param input The buffer containing the data to encrypt or decrypt. |
| * This pointer can be \c NULL if `ilen == 0`. |
| * \param output The buffer to where the encrypted or decrypted data |
| * is written. This pointer can be \c NULL if `ilen == 0`. |
| * \param tag The buffer to where the computed 128-bit (16 bytes) MAC |
| * is written. This must not be \c NULL. |
| * |
| * \return \c 0 on success. |
| * \return A negative error code on failure. |
| */ |
| int mbedtls_chachapoly_encrypt_and_tag( mbedtls_chachapoly_context *ctx, |
| size_t length, |
| const unsigned char nonce[12], |
| const unsigned char *aad, |
| size_t aad_len, |
| const unsigned char *input, |
| unsigned char *output, |
| unsigned char tag[16] ); |
| |
| /** |
| * \brief This function performs a complete ChaCha20-Poly1305 |
| * authenticated decryption with the previously-set key. |
| * |
| * \note Before using this function, you must set the key with |
| * \c mbedtls_chachapoly_setkey(). |
| * |
| * \param ctx The ChaCha20-Poly1305 context to use (holds the key). |
| * \param length The length (in Bytes) of the data to decrypt. |
| * \param nonce The \c 96 Bit (\c 12 bytes) nonce/IV to use. |
| * \param aad The buffer containing the additional authenticated data (AAD). |
| * This pointer can be \c NULL if `aad_len == 0`. |
| * \param aad_len The length (in bytes) of the AAD data to process. |
| * \param tag The buffer holding the authentication tag. |
| * This must be a readable buffer of length \c 16 Bytes. |
| * \param input The buffer containing the data to decrypt. |
| * This pointer can be \c NULL if `ilen == 0`. |
| * \param output The buffer to where the decrypted data is written. |
| * This pointer can be \c NULL if `ilen == 0`. |
| * |
| * \return \c 0 on success. |
| * \return #MBEDTLS_ERR_CHACHAPOLY_AUTH_FAILED |
| * if the data was not authentic. |
| * \return Another negative error code on other kinds of failure. |
| */ |
| int mbedtls_chachapoly_auth_decrypt( mbedtls_chachapoly_context *ctx, |
| size_t length, |
| const unsigned char nonce[12], |
| const unsigned char *aad, |
| size_t aad_len, |
| const unsigned char tag[16], |
| const unsigned char *input, |
| unsigned char *output ); |
| |
| #if defined(MBEDTLS_SELF_TEST) |
| /** |
| * \brief The ChaCha20-Poly1305 checkup routine. |
| * |
| * \return \c 0 on success. |
| * \return \c 1 on failure. |
| */ |
| int mbedtls_chachapoly_self_test( int verbose ); |
| #endif /* MBEDTLS_SELF_TEST */ |
| |
| #ifdef __cplusplus |
| } |
| #endif |
| |
| #endif /* MBEDTLS_CHACHAPOLY_H */ |